Patent Application
20220353614
Aspects disclosed herein may generally relate to a loudspeaker layout in a vehicle. Specifically, aspects disclosed herein may generally relate to a loudspeaker layout in a vehicle for generating low frequency audio outputs in individual sound zones.
Common loudspeaker arrangements in an interior of a car and other vehicles, include a multiplicity of loudspeakers distributed throughout the interior. For example, broadband loudspeakers, midrange loudspeakers and tweeters may be disposed, in the dashboard, in the doors, on the pillars, the rear shelf, etc. to provide various audio sources at various positions within the car interior. Such loudspeaker arrangements may be configured to provide a surround sound listening environment. Woofers are also utilized as part of a surround sound system that also include midrange loudspeakers and tweeters. These woofers may be installed in doors of the vehicle, in a rear end of a vehicle cabin, and/or in a trunk of the vehicle. One loudspeaker arrangement may produce individual sound zones (ISZ) in the vehicle cabin. It is generally desirable to provide sufficient isolation between zones in the vehicle particularly in relation to the low frequency energy range while generating audio in the vehicle cabin utilizing a surround sound system.
In at least one embodiment, a loudspeaker arrangement for a vehicle is provided. The loudspeaker arrangement includes a surround sound loudspeaker arrangement and at least one proximity woofer. The surround sound loudspeaker arrangement includes a plurality of surround woofers being positioned in a listening environment in the vehicle that defines a plurality of sounds zones to provide a first low frequency audio output having a first sound pressure level within the vehicle. The at least one proximity woofer is positioned about a first seat in a first sound zone of the vehicle, the at least one proximity woofer being configured to provide a second low frequency audio output in the first sound zone of the vehicle. The second low frequency audio output as provided by the at least one proximity woofer modifies the first sound pressure level to provide a target sound pressure level. The target sound pressure level corresponds to a final effective sound pressure level of an audio signal that is received by a listener.
In at least another embodiment, a loudspeaker arrangement for a vehicle is provided. The loudspeaker arrangement includes a plurality of surround woofers and at least one proximity woofer. The plurality of surround woofers are positioned in a listening environment of the vehicle that defines a plurality of sounds zones to provide a first low frequency audio output having a first sound pressure level in the plurality of sound zones. The at least one proximity woofer is positioned about a first seat in a first sound zone of the vehicle. The at least one proximity woofer is configured to provide a second low frequency audio output in the first sound zone of the vehicle, The second low frequency audio output as provided by the at least one proximity woofer modifies the first sound pressure level to provide a target sound pressure level. The target sound pressure level corresponds to a final effective sound pressure level of an audio signal that is received by a listener.
In at least another embodiment, a loudspeaker arrangement for a vehicle is provided. The loudspeaker arrangement includes a surround sound loudspeaker arrangement and at least one proximity woofer. The surround sound loudspeaker arrangement includes a plurality of surround woofers being positioned in a listening environment in the vehicle that defines a plurality of sounds zones to provide a first low frequency audio output having a first sound pressure level within the vehicle. The at least one proximity woofer is positioned about a first seat in a first sound zone of the vehicle, the at least one proximity woofer being configured to provide a second low frequency audio output in the first sound zone of the vehicle. The second low frequency audio output as provided by the at least one proximity woofer modifies the first sound pressure level to provide a target sound pressure level. The target sound pressure level corresponds to a final effective sound pressure level of an audio signal that is received by a listener. The plurality of surround woofers and the at least one proximity woofer are used in at least one or more of an active noise cancellation system, a bass management system, an engine order cancellation (EOC)/road noise cancellation (RNC) system, an individual surround sound system, and individual sound zones (ISZ) for the vehicle.
The embodiments of the present disclosure are pointed out with particularity in the appended claims. However, other features of the various embodiments will become more apparent and will be best understood by referring to the following detailed description in conjunction with the accompany drawings in which:
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are riot to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention.
It is recognized that directional terms that may be noted herein (e.g., “upper”, “lower”, “inner”, “outer”, “top”, “bottom”, etc.) simply refer to the orientation of various components as illustrated in the accompanying figures and the manner in which the proximity woofer(s) is positioned in the vehicle. Such terms are provided for context and understanding of the embodiments disclosed herein.
A loudspeaker system that generates audio in individual sound zones (ISZ) in a zoom may sufficiently deliver full-bandwidth separation in acoustic responses between different zones. In mid and high frequencies, the separation may be achieved passively by directivity control or shading. Additionally, the separation may be achieved through signal processing such as cross talk cancellation. In the low frequency range, for example, 20 Hz to 1000 Hz, the room acoustics may be deeply coupled with locations of the loudspeakers in the room (or vehicle cabin). Therefore, a layout of the loudspeakers may play a role in creating low frequency individual sound zones.
Traditionally, loudspeakers (or woofers) may be placed in surrounding areas of a room, or in the corners, to effectively excite room modes and to deliver low frequency energy to listening positions. Consider the example of a vehicle cabin, woofers may be placed in doors, in the rear end of the cabin, or in the trunk. Such a traditional woofer layout may have been acceptable for vehicle packaging requirements. However, this woofer layout has also been capable of delivering enough low frequency energy to various seat positions evenly, but not separately. In other words, the surround woofers may not be sufficient to create seat-to-seat separation.
To improve the separation between the zones in the vehicle in the low frequency audio range, additional woofers may be placed in closer proximity to listener's head in each zone. In this case, it may also be desirable to also keep the surround woofers in positions of the vehicle such as the door(s), rear end of the cabin, or in the trunk of the vehicle. In each zone, one or more proximity woofers may be placed next to a listener's head, behind the listener's head, or integrated into the headrest. Because of proximity of the woofer with respect to the listener's head, a smaller amount of energy may be needed to be transmitted from these loudspeakers to produce the energy level required for the listener in the vehicle. This aspect may ease the requirement of the woofer size, and in turn ease packaging requirements. Thus, by packaging surround woofers in either the door, rear of the vehicle, or in the trunk with proximity woofers that are positioned proximate to a listener's ears such as on a vehicle seat, such a condition yields sufficient separation between various zones (i.e., passengers) in the low frequency range of the audio output in the vehicle.
An audio controller 140 is operably coupled to the surround sound system 106 (e.g., the surround woofers 104a, 104h, 104c, and 104n and to the midrange and/or tweeter loudspeakers 130). The audio controller 140 transmits an audio signal to the surround sound system 106 to provide the surround sound effect. The audio controller 140 generally processes information used. in connection with an AM radio, FM radio, satellite radio, navigation system, user interface, display, wireless communication with mobile devices via Bluetooth, WiFi or other wireless protocols, etc.
The proximity woofers 250, 252, 254, 256 on the vehicle seats 112a, 112b, 112c, 112n in combination with the surround woofers 104a, 104b, 104c, and 104n have now been discovered to improve sound separation in the low frequency range between the various zones 120a, 120b, 120c, and 120n of the vehicle 110. For example, by combining surround woofers 104a, 104b, 104c, and 104n with the proximity woofers 250, 252, 254, and 256 being positioned in a respective zone 120a, 120b, 120c, and 120n; such an arrangement has been found to improve low frequency separation performance. In the low frequency ranges (e.g., less than 200 Hz), the listening environment 108 of the vehicle 110 exhibits various acoustical modes that may be formed by standing waves in space. These acoustical modes may be global across the entire listening environment 108 of the vehicle 110. To effectively manipulate (e.g., enhance or attenuate) certain vehicle cabin modes, the surround woofers 104a, 104b, 104c, and 104n are utilized in their respective surround positions in the vehicle 110 and the low frequency output from the audio from such woofers 104a, 104b, 104c, and 104n) coordinate (or coacts) with the low frequency output from the proximity woofers 250, 252, 254, and 256 to provide separate the low frequency output between the corresponding zones 120a, 120b, 120c, and 120n.
In general, the plots 450, 452, 454, and 456 illustrate a separation at different positions, if a bright zone is established at one particular seat position. In this case, magnitude spectra as labeled FL (upper left) in plots 450 (e.g., FL), 452 (e.g., FR), 454 (e.g., RL), and 456 (e.g., RR) indicate that the bright zone is at this position, and so on. Further, the magnitude spectra as shaded differently in each plot 450, 452, 454, and 456 also have a connection to the seat positions: FL, FR, RL and RR (the shading of the magna spectra can be matched to the shadings for FL, FR, RL, and RR in the legend (e.g., upper left hand side) for each plot 450, 452, 454, and 456). Hence, the upper left plot illustrates the separation that can be achieved between the various positions e.g., FR, RL, and RR), with respect to the FL position (bright zone).
As also shown, plot 452 depicts the audio performance of the surround woofers 104a-104n to create a bright zone at zone 120b (e.g., front right zone of the vehicle 110), plot 454 depicts the audio performance of the surround woofers 104a-104n to create a bright zone 120c (e.g., rear left zone of the vehicle 110), and plot 456 depicts the audio performance of the surround woofers 104-104n to create a bright zone 120n (e.g., rear right zone of the vehicle 110), while all remaining zones, of each ease, will always be dark zones. Each of these plots 452, 454, and 456 illustrate approximately a similar separation between the corresponding zones and these plots correspond to when only the surround woofers 104a-104n are in the surround sound system 106. This aspect may not provide sufficient ISZ performance, if the target is set, for example, to 20 dB as illustrated in all plots.
As also shown, plot 552 depicts the audio performance if the bright zone is at 120b (e.g., front right zone of the vehicle 110), plot 554 depicts the audio performance if the bright zone is at 120c (e.g., rear left zone of the vehicle 110), and plot 556 depicts the audio performance if the bright zone is at 120n (e.g., rear right zone of the vehicle 110), while again all remaining zones will be dark zones, for all of those cases. Each of these plots 552, 554, and 556 illustrate a comparable separation between the corresponding zones and these plots correspond to when only the proximity woofers 250, 252, 254, and 256 are employed in the vehicle 110. This aspect may not provide sufficient ISZ performance, if the target is set e.g. to 20 dB as illustrated in all plots.
Plot 650 illustrates that by combining the surround woofers 104a, 104b, 104c, and 104n with the proximity woofers 250, 252, 254, and 256; such an arrangement leads to an improvement over low frequency separation performance. In the low frequency range (e.g., less than 200 Hz), the listening environment 108 of the vehicle 110 exhibits various acoustical modes that may be formed by standing waves in space. These acoustical modes may be global across the entire listening environment 108 of the vehicle 110. To effectively manipulate e.g., enhance or attenuate) certain vehicle cabin modes, the surround woofers 104a, 104b, 104c, and 104n are utilized in their respective surround positions in the vehicle 110 for global modal control and the low frequency output from the audio from the proximity woofers 250, 252, 254, and 256 provide local enhancement to separate the low frequency audio between the corresponding zones 120a, 120b, 120c, and 120n.
As also shown, plot 652 depicts the audio performance if the bright zone is at 120b (e.g., front right zone of the vehicle 110), plot 654 depicts the audio performance if the bright zone is at 120c (e.g., rear left zone of the vehicle 110), and plot 656 depicts the audio performance if the bright zone is at 120n (e.g., rear right zone of the vehicle 110), in each of those cased, all remaining zones are established as dark zones. Each of these plots 652, 654, and 656 illustrate an improvement in separation between the corresponding zones. In general, the surround woofers may only be able to create standing waves or room modes, within the interior of the vehicle 110 (i.e., the surround woofers can create a global wave field which may be beneficial for the separation between individual positions and may be limited to generate enough contrast between individual positions) while proximity woofers may be able to control. the wave field locally, i.e., individually at each. position, and ear position of each zone. By utilizing the surround woofers that control room modes and a global wave field in combination of the proximity woofers that control the wave field of the audio locally al each zone, position, or ear position, etc., these attributes provide a low frequency separation between the respective zones 120a-120n of the vehicle 110.
As also shown, plot 752 depicts the audio performance if the bright zone is at 120b (e.g., front right zone of the vehicle 110), plot 754 depicts the audio performance if the bright zone is at 120c (e.g., rear left zone of the vehicle 110), and plot 756 depicts the audio performance if the bright zone is at 120n (e.g., rear right zone of the vehicle 110), While for each of those eases all remaining zones are established as dark zones. Each of these plots 752, 754, and 756 illustrate an improvement in separation between the corresponding zones.
While it has been noted that the proximity woofers in combination with the surround woofers improve low frequency separation performance, it is recognized that such a combination also yields improvements to individual engine order cancellation (FOC) or road noise cancellation (RNC) (i.e., generally to active noise cancellation (ANC)), independent surround zone, bass enhancement/management, engine sound synthesis (ESS), etc. First of all, all of these aspects may benefit from the proximity of those proximity woofers (even their smaller footprint (or dimension)) since, due to their proximity, and despite their small size, the proximity woofers are able to generate high SPL at the passenger's ears, which may be needed for ANC, bass enhancement/management, and ESS.
Second, particularly for ANC applications, due to the low latency and dose proximity of proximity woofers to the ears of the passengers is beneficial, since this relaxes, the otherwise limiting latency of the overall signal flow (from a reference sensor (e.g. microphone, accelerometer, RPM-sensor, etc.) via an optional A/D-converter, an ANC-filter, a D/A-converter, the loudspeaker (as represented by the proximity woofer), via the secondary path to the error microphone). Due to this lower, overall latency and high SPL (e.g., >=90-100 dBSPL) at the passenger's ears attributed to the proximity woofers, even at low frequencies, the proximity woofers may be well suited for ANC applications, in particular within car environments, as, due to those positive aspects, it is possible to expect not just an improvement in the ANC performance (higher noise reduction), but also an enlargement of the spectral range of operation, in which such an ANC performance can be achieved (e.g., the broadening of the useful spectral range).
Due to the lateral arrangement of the proximity woofers as positioned on the respective seats, it is possible to enhance an individual surround in a corresponding sound zone. The lateral arrangement of the proximity woofers generally corresponds to such speakers being mounted to directly face a passenger's ears (e.g., a corresponding proximity woofer faces a right ear and a corresponding proximity woofer faces a left ear). This aspect may enable binaural cues, which are especially useful to create a pleasant surround sound effect which may not be accomplished if the speakers are directly mounted into the headset and faces the back of the passenger's head. It is recognized that the proximity woofers may not have to be directly oriented to provide audio directly to the passenger's ears (e.g., be mounted with a 90 degrees angle to the ears), but that the proximity woofers can be orientated at a larger angle (e.g., 120 degrees). It is also recognized that the proximity woofers may be positioned in, for example, a corresponding zone that is defined by: (i) +/−40 cm in relation to an overall width of the backrest of the vehicle seat, (ii) 8 cm below a vehicle occupant's ear while the vehicle occupant is normally positioned on the vehicle seat, and/or (iii) 8-17 cm in front of a headrest (or to a rear of the headrest) of the vehicle seat. Thus, the proximity woofers as disclosed in connection with
In connection with bass management and individual ANC/RNC/EOC (or individual zones in relation to ANC/RNC/EOC), the combination of the surround woofers and the proximity woofers are also beneficial for the following reasons below. For example, often, proximity woofers may be, despite their close proximity to the listeners, especially at low frequencies (e.g., approximately f<50 Hz) too weak (i.e., the proximity woofers provide at a low frequency, a low SPL) in comparison to low frequency output provided by surround woofers. In general, at these low frequencies, the sound pressure chamber effect of the cabin of the vehicle (or the listening environment of the vehicle) is already present, leading to an amplification of the sound pressure. This may not be achieved by proximity woofer alone, since proximity woofers may not be strong enough to stimulate/erect a complete sound field within the interior of the vehicle. The surround woofers may be strong enough to do this since the surround woofers are generally large and are mounted to components in the vehicle that have more volume than that of space or volume that the proximity woofers are enclosed within. Hence, the combination of, the proximity and surround woofers lead to an amplification of sound pressure which may also enlarge the useful spectral range also to very low frequencies.
In operation 802, the audio controller 140 transmits an audio signal to the surround sound system 106 for audio playback in the listening environment 108. The surround woofers 104 provide a first low frequency audio output having a first sound pressure level for the audio signal in the, vehicle 110.
In operation 804, the audio controller 140 transmits the audio signal to each proximity woofer 250, 252, 254, 256 in a corresponding zone. Each of the proximity woofers 250, 252, 254, 256 provides a second low frequency audio output in a corresponding zone 120.
In operation 806, the second low frequency audio output as provided by proximity woofers 250, 252, 254, 256 modifies the first sound pressure level to provide a target sound pressure level. The target sound pressure level may generally correspond to a final effective sound pressure level (e.g., 0 or 120 dBSPL) of an audio signal that is received by a listener. In one example, the final effective sound pressure for ISZ and/or ANC applications may be 0 dBSPL. The other values that fall within the final effective sound pressure level (e.g., 0 to 120 dBSPL) may be applicable for audio and bass management applications. The second low frequency audio output as provided by the proximity woofers 250, 252, 254, 256 may increase the first sound pressure level associated with the output from the surround sound system 106 and the corresponding surround woofers 104 to provide the final effective sound pressure. The surround woofers can provide enough power (or enough of the sound pressure level) however, the surround woofer may not be able to individually control an acoustical sound field. The inclusion of the proximity woofers provides a local solution in controlling the acoustical sound field.
In order to enable manipulation of the effective sound pressure of the low frequency audio output provided by the surround woofers 104, the received sound pressure level of low frequency audio output of the proximity woofer 250, 252, 254, 256 should be at least equal, or greater than the sound pressure of the low frequency audio output in the corresponding sound zone 112a-112n. By manipulating control of the first sound pressure level, this aspect may benefit the ISZ, ANC, bass management, individual surround sound zone, and ESS applications in the vehicle 110. In general, the modification of the first sound pressure level associated with the output from the surround sound system 106 generally provides greater control over the sound pressure for each corresponding sound zone 112a-112n for ISZ, ANC, individual surround sound in the zones, and ESS applications. Bass management may also be improved overall in the listening environment due the cumulative effect of modifying the sound pressure individually at each zone which in turn bolsters the performance of the effect of the bass overall for the entire listening environment 108.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/057988 | 10/25/2019 | WO |
